Featwise
Jubidara is physically as fast as 8 gated Gai:
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And he struggled to hit a weakened intangible Obito simply because speed matter less against intangibility
Naruto showed difficulties to dodge the chakra arms
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He even said they are insanely fast
And Naruto is faster than Eight Gated Gai, yet Kakashi(in his flying Susanoo) moved faster than an attack even him had difficulties to counter
By feats, Kakashi can easily react to 8 gated Gai, let alone turn intangible
Intangibility can be maintain during 5 minutes at a time. The second he can't use it can be replaced by a defense as hard as Perfect Susanoo that should at the very least be capable to defend against one 8 gated Gai's attacks and the cycle continues over and over, making it almost close to impossible to 8 gated Gai to actually hit Kakashi
Add into that the drawbacks of the 8 gates and Kakashi could snipe him anytime at that point
Portrayal-wise
Parallels(they are supposed to be viewed on equal footing in terms of abilities):
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One eyed MS Kakashi > Gai(without final gate):
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8 Gated Gai > One eyed MS Kakashi:
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Speculation, but i guess 2 eyed MS Kakashi is supposed to have taken the lead once again(especially since he is fuelled in Obito's chakra and is actually useful against a superior opponent):
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